Data recording method

Abstract

A data recording apparatus reverses the bit order of each of n-bit codes assigned respectively to 2 n frame data in the order of a normal-speed play, rearranges the frame data based on the reversed n-bit codes, and then records the rearranged frame data in that order onto a recording medium. A data reproducing apparatus reads out, from the recording medium, frame data corresponding in number to the reciprocal of the multiple in an aimed play speed and stored the read-out frame data in a buffer memory or the like. The data reproducing apparatus then reads out the stored frame data from the buffer memory or the like in a predetermined order in accordance with the aimed play speed. The data reproducing apparatus can realize such a high-speed play as were more than its data read performance. Besides, wasteful operations in a high-speed play can be eliminated and the load on the reading head unit of the data reproducing apparatus can be relieved.

What is claimed is:  
     
       1. A Data recording method comprising the steps of: 
       assigning n-bits codes respectively to 2 n  frame data (where n is positive integer) in the order of a normal-speed play;  
       reversing the bit order of each of the n-bits codes;  
       defining a recording order of the frame data based on the reversed n-bit codes; and  
       recording the frame data in the defined recording order onto a recording medium.  
     
     
       2. The method according to  claim 1 , wherein the 2 n  frame data are motion JPEG data. 
     
     
       3. A data recording apparatus comprising: 
       a frame rearranging unit, that rearranges 2 n  frame data (where n is a positive integer) based on n-bit codes obtained by reversing the bit order of each of n-bit codes assigned respectively to the frame data in order of a normal-speed play; and  
       a recording unit, that records the rearranged frame data in a rearranged order onto a recording medium.  
     
     
       4. The apparatus according to  claim 3 , wherein the 2 n  frame data are motion JPEG data. 
     
     
       5. A data reproducing method comprising the steps of: 
       reading out frame data corresponding in number to the reciprocal of the multiple in an aimed play speed, in the recording order from a recording medium on which 2 n  frame data (where n is a positive integer) having been rearranged based on n-bit codes obtained by reversing the bit order of each of n-bit codes assigned respectively to the frame data in the order of a normal-speed play, are recorded in the order after the rearrangement;  
       storing the read-out frame data in a buffer; and  
       reading out the stored frame data.  
     
     
       6. The method according to  claim 5 , wherein the 2 n  frame data are motion JPEG data. 
     
     
       7. A data reproducing apparatus comprising: 
       a reading-out unit, that reads out frame data corresponding in number to the reciprocal of the multiple in an aimed play speed, in the recording order from a recording medium on which 2 n  frame data (where n is positive integer) having been rearranged based on n-bit codes obtained by reversing the bit order of each of n-bits codes assigned respectively to the frame data in the order of a normal-speed play, are recorded in the order after the rearrangement;  
       a memory unit, that stores the read-out frame data; and  
       a memory reading-out unit, that reads out the stored frame data from the memory unit.  
     
     
       8. The apparatus according to  claim 7 , wherein the 2 n  frame data are motion JPEG data. 
     
     
       9. A recording medium on which 2 n  frame data (where n is a positive integer) having been rearranged based on n-bit codes obtained by reversing the bit order of each of n-bit codes assigned respectively to the frame data in the order of a normal-speed play are recorded in the order after the rearrangement. 
     
     
       10. The medium according to  claim 9 , wherein the 2 n  frame data are motion JPEG data. 
     
     
       11. A method for recording and reproducing data from a file including a plurality of frame data sequentially ordered in the file, wherein fewer than all of the frame data are required for playback at a speed above normal-play speed, comprising the step of: 
       recording the plurality of frame data to be played so that all of the frame data that are required for playback at the speed above normal-play speed are arranged at a frontward portion of the file.